N-t-Butyl-benzamide, N-t-butyl-4-bromobenzamide, N-t-butyl-4-nitrobenzamide, etc. are known to be useful as a medicament for treating neurodegenerative disorders such as Parkinson's disease, multiple sclerosis, Alzheimer's disease and the like (WO 95/28153, WO 96/31462). N-t-Butyl-3-chloro-2-pyridinecarboxamide, N-(2-hydroxy-1,1-dimethylethyl)-6-chloro-2-pyridinecarboxamide, etc. are known to be useful as a herbicide (JP 48-26918(A), JP 60-72803(A), JP 61-151174(A)).
It has been known that N-t-butyl-4-fluorobenzanide, N-t-butyl-2-fluorobenzamide, N-(2-hydroxy-1,1-dimethylethyl)-2,4,5-trifluorobenzamide, N-(2-hydroxy-1,1-dimethylethyl)-2,5-difluorobenzamide, N-(2-hydroxy-1,1-dimethylethyl)-2-fluorobenzamide, N-(2-hydroxy-1,1-dimethylethyl)-5-chloro-2-fluorobenzamide, N-(2-hydroxy-1,1-dimethylethyl)-2-fluoro-6-iodobenzamide, N-(2-hydroxy-1,1-dimethylethyl)-2,6-difluorobenzamide, N-(2-hydroxy-1,1-dimethylethyl)-2-chloro-4-fluorobenzamide, etc. were produced as synthetic intermediates (EP 511073, WO 89/06649, J. Org. Chem., 52, 713(1987), J. Org. Chem., 53, 345(1988), EP 538231, U.S. Pat. No. 3,985,889, etc.).
However, these documents do not disclose that the amide derivatives are effective for treating retinal neurodegenerative disorders.